PROJECT SUMMARY/ABSTRACT Aphasia is a debilitating language disorder that persists in 30-50% of people who experience a stroke. Augmentative and alternative communication (AAC) is typically used to help people with aphasia compensate for chronic language deficits. That is, AAC is used as an alternative to spoken language, when response to language recovery treatment plateaus. In the proposed project, we will implement AAC in a novel manner; one that seeks to facilitate language recovery rather than compensate for post-stroke aphasia deficits. The long-term objectives of the project are to (1) demonstrate the value of AAC for recovery, which would prompt clinicians?and people with aphasia?to use AAC as an adjunctive treatment, alongside usual care and (2) build a predictive model, via behavioral and neurobiological markers, to identify which people with aphasia would respond most effectively to this combined treatment approach. The objective of this R15 is to afford students the opportunity to participate in behavioral and biomedical research while examining the effect of AAC treatment in 20 people with chronic (> 12 months), post-stroke aphasia. We will use functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) to identify the neurobiological mechanism underlying AAC-induced language recovery and variability in treatment response. We propose a 2 (groups) X 4 (measurement time points) switching replications design to examine these Specific Aims: ? Aim 1: Determine the therapeutic effect of providing AAC treatment during the chronic, post-stroke aphasia phase. ? Aim 2: Evaluate underlying changes in functional and structural neuroanatomy associated with AAC treatment. ? Exploratory Aim: Identify treatment responder subgroups based on data collected in Aim 1 and Aim 2. The proposed project is the necessary step in a line of research that will lead to enhanced language recovery outcomes for people with stroke-induced aphasia. This R15 will also contribute to the ability to identify, a priori, who will respond to this particular AAC intervention and who will not, which will ultimately reduce the cost of healthcare for stroke recovery by implementing the most effective treatment possible. Importantly, identification of non-responders will generate data required to fine-tune the AAC treatment for this subgroup. This R15 is directly in line with the NIDCD?s Priority Area 3: Improving Diagnosis, Treatment, and Prevention. Specifically, the project aims to develop novel AAC approaches and use neurobiomarkers to identify treatment responders.